Method and device to reduce asphaltene and paraffin accumulations in wells

ABSTRACT

An oil well capsule to reduce the paraffin and asphaltene which accumulate on the walls of the pipes which are used to bring the oil up from underground deposits, and a method of using said oil well capsule. An oil well capsule having a shell encapsulating a chemically active mass wherein said chemically active mass consists essentially of alkaline or alkaline earth metal.

CROSS-REFERENCE TO RELATED APPLICATION

[0001] This application is a continuation of and claims priority toco-pending application Ser. No. 09/886,077, filed Jun. 20, 2001.

FIELD OF THE INVENTION

[0002] The instant invention relates to methods and articles forcleaning oil wells and more particularly to articles and methods forcleaning pressure differential oil wells.

BACKGROUND

[0003] The buildup of paraffin and asphaltene in oil wells is a problemin the oil industry. Paraffin and asphaltene as well as other impuritiesaccumulate on the walls of the pipes which are used to bring the oil upfrom underground deposits. If not removed, these accumulations willeventually build up to the point that the flow of oil is significantlyreduced and the well may become inoperable. Currently, paraffin andasphaltene buildup is handled by periodically pumping very hot oil,augmented by cleansing additives, down the pipe in order to melt theaccumulations. The melted paraffin and asphaltene are then forced out ofthe well by the continuing upward flow of oil. Moreover, the hot oilmethod must be repeated quite often. Paraffin and

CROSS-REFERENCE TO RELATED APPLICATION

[0004] This application is a continuation of and claims priority toco-pending application Ser. No. 09/886,077, filed Jun. 20, 2001.

FIELD OF THE INVENTION

[0005] The instant invention relates to methods and articles forcleaning oil wells and more particularly to articles and methods forcleaning pressure differential oil wells.

BACKGROUND

[0006] The buildup of paraffin and asphaltene in oil wells is a problemin the oil industry. Paraffin and asphaltene as well as other impuritiesaccumulate on the walls of the pipes which are used to bring the oil upfrom underground deposits. If not removed, these accumulations willeventually build up to the point that the flow of oil is significantlyreduced and the well may become inoperable. Currently, paraffin andasphaltene buildup is handled by periodically pumping very hot oil,augmented by cleansing additives, down the pipe in order to melt theaccumulations. The melted paraffin and asphaltene are then forced out ofthe well by the continuing upward flow of oil. Moreover, the hot oilmethod must be repeated quite often. Paraffin and asphaltene buildup isalso handled by use of a device which “reams out” the paraffin andasphaltene. The reaming method is time consuming and does not remove allthe deposits. Further, existing methods cannot be used to restore oldpipes which have been shut down because of excessive paraffin andasphaltene accumulations. Further, existing methods of accumulationremoval require a crew of several workers to operate. Moreover, existingmethods do not work efficiently with under sea oil wells. Moreover,existing methods require the flow of oil to be interrupted during theperiod of the cleaning process.

[0007] The differing kinds of oil wells include the gas-lift well, whichbrings oil to the surface largely through naturally occurring pressuredifferentials, the rod and pump well, which uses a rod to act as a pumpto bring the oil to the surface, and the centrifugal pump well, where apump is placed in the depths of the well to create a pressuredifferential to bring oil to the surface.

[0008] The following represents a list of known related non domesticart: Patient Inventor Issued Russian Fed. Patent 2028447 Belyaev Oct.15, 1991 Russian Fed. Patent 2105867 Katzyn et al. Jul. 11, 1997 RussianFed. Patent 2122628 Belyaev Jun. 20, 1997

[0009] None of the above inventions and patents, taken either singularlyor in combination, is seen to describe the instant invention as claimed.Thus solving the aforementioned problems is desired.

[0010] The following represents a list of known related domestic art:Patent Inventor Issued U.S. Pat. No. 3,402,770 Messenger Sep. 24, 1968U.S. Pat. No. 3,531,409 Seffens et al. Sep. 29, 1970 U.S. Pat. No.3,914,132 Sutton Oct. 21, 1975 U.S. Pat. No. 4,125,458 Bushnell, et al.Nov. 14, 1978 U.S. Pat. No. 4,207,193 Ford, et al. Jun. 10, 1980 U.S.Pat. No. 4,614,236 Watkins et al. Sep. 30, 1986 U.S. Pat. No. 4,775,489Watkins et al. Oct. 4, 1988

[0011] The teachings of each of the above-listed domestic citations(which does not itself incorporate essential material by reference) areherein incorporated by reference. None of the above inventions andpatents, taken either singularly or in combination, is seen to describethe instant invention as claimed. Thus solving the aforementionedproblems is desired.

[0012] Heretofore, an article and method for reducing asphaltene andparaffin accumulations in oil wells through use of a capsule enclosing achemically active mass which is inserted into an oil well and whichslides down the solid well, reacting with and reducing asphaltene andparaffin accumulations as it travels down the well, has not previouslybeen provided. An article and method for reducing asphaltene andparaffin accumulations in oil wells through use of a capsule enclosing achemically active mass with a gel precursor core which is inserted intoan oil well and which slides down the solid well, reacting with andreducing asphaltene and paraffin accumulations as it travels down thewell, has not previously been provided. An article and method forcoating the inside of oil wells with a gel to impede the startup andgrowth of paraffin and asphaltene has not previously been provided. Anarticle and method for reducing asphaltene and paraffin accumulations inoil wells, and providing a protective layer to impede the growth ofasphaltene and paraffin, which requires three or fewer individuals tooperate has not previously been provided. An article and method forreducing asphaltene and paraffin accumulations in oil wells, andproviding a protective layer to impede the growth of asphaltene andparaffin, which can be used to open up for use oil wells that have beenabandoned due to excessive accumulation of paraffin and asphaltene hasnot previously been provided. An article and method for reducingasphaltene and paraffin accumulations in oil wells, and providing aprotective layer to impede the growth of asphaltene and paraffin, whichcan be used for under sea wells, has not previously been provided.

OBJECTS AND ADVANTAGES

[0013] Accordingly, it is an object to provide novel articles andmethods for solving the above-mentioned problems. In particular, it isan object to provide an article and method for reducing asphaltene andparaffin accumulations in oil wells through use of a capsule enclosing achemically active mass with a gel precursor core which is inserted intoan oil well and which slides down the solid well, reacting with andreducing asphaltene and paraffin accumulations as it travels down thewell. It is an object to provide an article and method for coating theinside of oil pipes with a gel to impede the startup and growth ofparaffin and asphaltene. It is an object to provide an article andmethod for reducing asphaltene and paraffin accumulations in oil wells,and providing a protective layer to impede the growth of asphaltene andparaffin, which requires three or fewer individuals to operate. It is anobject to provide an article and method for reducing asphaltene andparaffin accumulations in oil wells, and providing a protective layer toimpede the growth of asphaltene and paraffin, which can be used to openup for use oil wells that have been abandoned due to excessiveaccumulation of paraffin and asphaltene. It is an object to provide anarticle and method for reducing asphaltene and paraffin accumulations inoil wells, and providing a protective layer to impede the growth ofasphaltene and paraffin, which can be used for under sea wells. It is anobject to provide an article and method for reducing asphaltene andparaffin accumulations in oil wells during the cleaning period withoutsignificantly interrupting the flow of oil in the well. It is a furtherobject of the invention to provide improved elements and arrangementsthereof for the purposes described which is inexpensive, dependable andfully effective in accomplishing its intended purposes. These and otherobjects of the present invention will become readily apparent uponfurther review of the following specification and drawings.

[0014] The novel articles and methods provide a number of advantages.Advantage arises from the reduction of asphaltene accumulations in anoil well treated with the disclosed invention. Advantage arises from thereduction of paraffin accumulations in an oil well treated with thedisclosed invention. Advantage arises from the adaptability of thepresent invention to use with under sea wells. Advantage arises from theability of the present invention to reopen closed oil wells throughtreatment by the present invention. Advantage arises from the small workcrew that is needed or use of the present invention. Advantage arisesfrom the ability to clean the well with the presently describedinvention without significantly interrupting the flow of oil during thecleaning period.

[0015] Additional objects and advantages of the invention will be setforth in part in the description which follows, and in part will beobvious from the description, or may be learned by practice of theinvention. The objects and advantages of the invention may be realizedand attained by means of the instrumentalities and combinationsparticularly pointed out in the appended claims. Further benefits andadvantages of the embodiments of the invention will become apparent fromconsideration of the following detailed description given with referenceto the accompanying drawings, which specify and show preferredembodiments of the present invention.

[0016] Potential customers for articles and methods that meet theseobjects include oil companies, oil well operators and suppliers,engineers, scientists, among others.

BRIEF DESCRIPTION OF THE DRAWINGS

[0017]FIG. 1 shows an embodiment of the present invention with the gelprecursor option.

[0018]FIGS. 2 through 4 show an embodiment of the present invention inoperation.

DETAILED DESCRIPTION

[0019] Before beginning a detailed description of the subject invention,mention of the following is in order. When appropriate, like referencematerials and characters are used to designate identical, corresponding,or similar components in differing figure drawings. The figure drawingsassociated with this disclosure typically are not drawn with dimensionalaccuracy to scale, i.e., such drawings have been drafted with a focus onclarity of viewing and understanding rather than dimensional accuracy.An attempt has been made specifically to point out any dimensions,tolerances, etc., which are important.

[0020] An oil well capsule is provided for use on pressure differentialwells. With reference to FIG. 1, an oil well capsule 10 comprises achemically active mass 12 wrapped in a shell 14. A gel precursor 16within a hollowed core 24 of said chemically active mass may optionallybe provided. The capsule preferably has the shape of a cylindrical tube.Capsule diameter and length can be sized to accommodate differing oilwells In the preferred embodiment, length is 500 millimeters (mm) anddiameter is 36 mm.

[0021] The shell 14 wraps the chemically active mass. In the preferredembodiment, the shell is made of ordinary aluminum foil. The shell hasthree components: a rectangular body 18 with length and height, and twoend pieces 20. The foil has a thickness in the range 0.01 to 0.4 mm. Thediameter of the end pieces is preferably 36 mm. The two end pieces 20are circular in shape and form the terminals of the capsule. The lengthof the body is preferably 500 mm. The height of the body corresponds tothe diameter of the capsule such that the height equals 10 mm plus theproduct of Pi, estimated as 3.14, multiplied by the diameter. The 10 mmin the height calculation represents the excess over-cover of thecapsule when the body is wrapped around the chemically active mass tomake the capsule. The height of the body is 123 mm. The shell can havediffering dimension to adapt to different sizes of the capsule.

[0022] The chemically active mass consists essentially of alkaline oralkaline earth metal, and can be sodium, lithium, potassium, calcium,strontium, barium or combinations of them. In the preferred embodiment,the chemically active mass consists essentially of sodium.

[0023] To form the chemically active mass into a cylindrical form to bewrapped by the shell, alkaline or alkaline earth metal in powdered formis heated to the melting point temperature of the metal, under a smalllayer of paraffin to prevent metal interaction with oxygen. Thechemically active mass is then cast in a cylinder mold. Alternatively,the metal is pressed in the cylinder form without melting due toplasticity of the metal at room temperature.

[0024] A weight increaser can be added to the chemically active mass.The weight increaser consists essentially of inert powder with densitynot less than 2 grams per centimeter cubed (g/cm³). Inert powder ischosen from the selection consisting of barite powder, sand, and ironpowder. The weight increaser can be added by pressing the weightincreaser into the heated chemically active mass. This can beaccomplished by distributing the weight increaser generally uniformly onthe surface of the chemically active mass and then pressing thedistributed weight increaser into the mass with a plan press before theresulting mass is formed into a cylindrical form. Alternatively, thechemically active mass can be put into a cylindrical press form and theweight increaser distributed along the axis when heated, and thenpressing the press form halves together. Yet another equivalent mannerin which to add weight increaser includes melting the chemically activemass under a small layer of paraffin, or under the inert gas atmosphere,e.g. argon or nitrogen, mixed with weight increaser in a 10 to 1 ratio,and stirring, cooling, and forming.

[0025] A gel precursor within a core of said chemically active mass canbe provided. A gel precursor consists essentially of aluminum orscandium. A core in the chemically active mass is prepared for receivingthe gel precursor by mechanically pressing out a cylindrical cavity inthe chemically active mass. Preferably, the pressing out occurs beforethe shell is put on the chemically active mass. In the preferredembodiment a hard rod of diameter 8 to 10 mm and height 500 mm is pushedinto the chemically active mass, roughly in the center of said mass, anddownward to within 10 to 15 mm of the opposite end of the device. Therod is then removed. The resulting hollowed core 24 is filled withpressed aluminum or scandium tablets (diameter 8-10 mm) or aluminum orscandium powder, to within 10-15 mm of the top of the cavity. The coreis then plugged with a cork 22 fashioned from the chemically active massmaterial. The height of the cork is 10-15 mm and diameter is 8-10 mm.

[0026] The shell body and end pieces are placed on a heat source.Preferably, the heat source is a steel slab, preferably having athickness approximately 10 mm and with length and width a little morethan the length and width of the shell body and end pieces, which isplaced on a heated electric stove. Heat source can be copper, or anyother metal which can be heated. Can be on a basic kitchen stove, withproper dimensions. Heated metal to be generally uniform temperature whenheated.

[0027] Shell can be treated with melted bitumen. The shell is heated tothe temperature at which bitumen melts, preferably 70 to 90 degreesCelsius. Bitumen is spread on the internal surfaces of the body and endpieces, by putting a piece of bitumen on the surfaces, and spreading thepiece as the bitumen melts. In the preferred mode, the bitumen is spreadby use of a brush. Preferably, the thickness of the bitumen spreadshould be in the range of 0.1 mm to 0.5 mm. Alternatively, instead ofbitumen, another hydrocarbon composition can be used, such as acomposition consisting essentially eighty percent mineral oil and twentypercent paraffin or polypropylene, or combinations of them.

[0028] After the shell components have been heated and treated, thechemically active mass is placed on the shell body and rolled up leavingan open ended capsule, cylindrical in shape. The shell end pieces arethen placed on each end and the overlap from the shell body is formedaround the ends of the cylinder.

[0029] To get additional insulation to the oil well capsule to protectit from interaction with oxygen, melted paraffin can be spread with abrush on the outer surface of the oil well capsule as assembled.

[0030] Referring to FIGS. 2 through 4, in operation, the oil wellcapsule is prepared for insertion in an oil well by cutting a terminalin the end of the capsule, and then the capsule is inserted into thehead of a pressure differential oil well. The reaction starts when themetal contacts the water in the well. The capsule is heavy enough thatit will slowly slide down the pipe. It generates a temperature highenough to melt the paraffin and asphaltene accumulated on the inside ofthe oil pipes. The general reaction formula is as follows:

2M+2H₂O=2MOH+H₂+heat

6MOH+2R=2(MO)₃R(gel)+3H₂+heat

[0031] Where M is an alkaline or alkaline earth metal and R is aluminumpowder or scandium powder. The H₂O can come from any type of water,including salt water.

[0032] As shown in FIGS. 2 through 4, as the capsule slides down thewell, it consumes itself in the process of generating enough heat tomelt the paraffin and asphaltene. Eventually it is consumed with noresidue remaining in the pipe.

[0033] This method significantly increases the time between oil wellcleanings. With traditional cleaning methods, the crystallizationcenters of the paraffin and aslphaltene accumulations remain on the oilwell pipe walls, with the result that the build up of the accumulationsresumes as soon as the wells have been cleaned. Conversely, the oil wellcapsule of the present invention increases the temperature in the areawhere it is applied to a level higher than the congealing point ofparaffin hydrocarbon. This makes it possible to remove completely theparaffin crystallization centers from the oil well walls and preventsolid deposits on them.

[0034] When the oil well capsule is provided with a gel precursor, asthe capsule descends, the gel precursor in the middle of the capsule istransformed to gel by the chemical reaction and is deposited on theinside of the oil wells. This gel acts like a grease and preventsparaffin accumulations. The gel sticks to the oil well walls and remainson the walls for a long time which then makes it difficult for newaccumulations of paraffin and asphaltene to begin.

[0035] With the present invention using the gel precursor, the timebetween oil well cleanings can be increased by anywhere from 3 to 8times. That is, if the normal cleaning period is month, it can beextended from anywhere from 3 to 8 months, depending upon the chemicalcomposition of the oil being pumped.

[0036] It will, of course, be understood that modifications of theinvention, in its various aspects, will be apparent to those skilled inthe art, some being apparent only after study, others being matters ofroutine mechanical, chemical and electronic design. No single feature,function or property of the preferred embodiment is essential. Otherembodiments are also possible, their specific designs depending upon theparticular application. As such, the scope of the invention should notbe limited by the particular embodiments herein described but should bedefined only by the appended claims and equivalents thereof.

We claim:
 1. An oil well capsule to reduce and prevent asphaltene andparaffin accumulations in pressure differential oil wells, comprising: ashell; and a chemically active mass consisting essentially of one ormore alkaline or alkaline earth metals encapsulated within said shell,wherein said shell is consumed by the reaction of said chemically activemass with water.
 2. The oil well capsule of claim 1, further comprisinga coating of paraffin on said shell for insulation.
 3. The oil wellcapsule of claims 1, wherein a weight increaser additive is included inthe chemically active mass so that the resulting capsule density is morethan one gram per centimeter cubed.
 4. The oil well capsule of claim 1,wherein said shell is aluminum foil.
 5. The oil well capsule of claim 4,wherein the inside of the shell has a coating of bitumen.
 6. An oil wellcapsule to reduce asphaltene and paraffin accumulations in pressuredifferential oil wells, comprising: a shell; a chemically active massconsisting essentially of one or more alkaline or alkaline earth metalsencapsulated within said shell; and a gel precursor disposed within ahollowed core of said chemically active mass wherein said gel precursorconsists essentially of a powdered metal selected from the group ofaluminum and scandium.
 7. The oil well capsule of claims 6, furthercomprising a coating of paraffin on said shell for insulation.
 8. Theoil well capsule of claims 6, wherein a weight increaser additive isincluded in the chemically active mass so that the resulting capsuledensity is more than one gram per centimeter cubed.
 9. The oil wellcapsule of claim 6, wherein said shell is aluminum foil.
 10. The oilwell capsule of claim 9, wherein the inside of the shell has a coatingof bitumen.
 11. An oil well capsule to reduce asphaltene and paraffinaccumulations in pressure differential oil wells, comprising: analuminum foil shell; a chemically active mass consisting essentially ofalkaline or alkaline earth metal encapsulated within said shell; and agel precursor chosen from the group of aluminum and scandium disposedwithin a hollowed core of said chemically active mass.
 12. The oil wellcapsule of claims 11, wherein a weight increaser additive is included inthe chemically active mass so that the resulting capsule density is morethan one gram per centimeter cubed.
 13. A method of reducing andpreventing asphaltene and paraffin accumulations in pressuredifferential oil wells, comprising the steps of: enclosing a chemicallyactive mass in a shell wherein said chemically active mass consistsessentially of alkaline or alkaline earth metal, and wherein said shellis consumed by the reaction of said chemically active mass with water;opening one end of said shell to expose the chemically active mass;placing said shell into a pressure differential well, wherein thechemically active mass exposed by the opening of said shell reacts tothe water in said well; releasing said shell; and consuming paraffin andasphaltene accumulations in said well through the heat generated by thereaction of said chemically active mass with the water in said well.